Corn oil has gained considerable momentum for use as a biodiesel. Corn oil also is used extensively in animal (e.g., poultry, swine, and cattle) feed. Thus the ability to obtain oil as part of the ethanol recovery process from corn is more important than ever. For every bushel of corn, there is approximately 1.5 pound of corn oil available for extraction.
To obtain ethanol and oil, a corn kernel typically undergoes fractionation to separate the various parts of the kernel: endosperm, germ, and the outer skin known as bran. To produce ethanol, starch contained in the endosperm must be fermented, whereas the corn's germ contains about 85% of the kernel's oil. Corn oil typically is obtained by pressing fractionated corn particles and extracting the oil with a solvent, such as hexane. To isolate the corn oil, the solvent is evaporated, recovered, and recycled. However, this method can be undesirable with respect to the use of organic solvent and the percent oil recovery is not very high.
Thus there remains a need to improve corn processing to improve the oil yield of the process and/or avoid the use of organic solvent.